The invention relates to a wireless network comprising at least a base station and a plurality of assigned terminals for exchanging user data and control data.
In the document “ETSI SMG2, Meeting no. 24, Cork, Ireland, 1-5 Dec. 1997, Tdoc SMG2 359/97, Concept Group Alpha—Wideband Direct-Sequence CDMA (WCDMA), EVALUATION DOCUMENT (3.0), part 1: System Description, Performance Evaluation”a radio network operating according to the CDMA method (CDMA—Code-Division Multiple Access) is proposed. The radio network comprises a plurality of radio cells having each a base station and terminals or mobile stations located therein. After a terminal has been registered and synchronized, it transmits a random-access burst over a contention channel which is denoted a Random-Access CHannel RACH, for example, when a user channel is requested. The random-access burst comprises a preamble part and a data part. The preamble part comprises 16 symbols (preamble sequence) which is spread by an orthogonal Gold code (preamble code). The orthogonal Gold code contains 256 chip intervals. The data part contains a field with an identification for the terminal, a field for featuring the requested service (short packet transmission, dedicated—channel set-up, etc.), an optional field for data packets (optional user packet) and a CRC field for error detection. A random-access burst received from a base station is supplied via a matched filter, a preamble correlator, and a peak detector to a circuit portion estimating the time delay of the data part, which circuit portion controls a RAKE circuit for the evaluation of the data part. Thus, a peak detection based on a correlation is used here with subsequent message decoding. The RACH channel is permanently available then (permanent channel).